Remedial Work to Window Reveals in dry lined homes

It is important to properly insulate round windows. Traditionally a lot of thermal bridges have routinely been built into our window details. For example by using masonry to close the cavity at the reveal, metal lintels that extend from inside to outside (how insane is that!). Additionally insulation is often not present under windows and even in the reveals due to poor workmanship or incorrect installation.

Draughts are frequently present under window boards, either emanating from the cavity or sometimes directly from outside. This coupled with this frames that are not always fully sealed to the masonry allowing draughts to enter; these draughts can most easily detected by noticing blackening of the cracks or dark shadowy streaks on the frames. We found a couple of extreme examples of draughts where it was possible to see straight over the window head from indoors or straight out under the window board and across the top of the cavity, and on out under the outside window sill and straight down the garden! Always look for cracks and gaps first then check with the back of your hand feel for draughts, the ultimate search weapons are feathers, lit candles, infra red thermometers and thermal imaging cameras.

The following set of pictures illustrates how to rectify window reveal and window board problem in homes that have been dry lined.

A typical window reveal before we started, note some damp marking to the bottom due to condensation in turn due to the reveal being so cold.

Taking a peek at the window reveal behind the reveal lining, this was covering a multitude of sins.

The plasterboard fully removed from a window reveal, note the presence of thermal bridging made worse by the use of bricks (just visible next to triangular plaster dob). Also note that there are lots of gaps between the masonry and the vertical dpc, draughts could blow behind the reveal lining and on round the corner and behind the wall lining boards. Hence my expression “like living in a plasterboard tent”.

Having almost finished cutting out the masonry return ready for insulation and the thermal lining.

Insulation added in the cavity and belt and braces foam to the edge of the wall lining board.

Thermal lining board added, this actually a piece of composite plasterboard with insulation bonded to the back of it.

A refinished reveal ready to redecorate

Carefully filling the space between the wall (note the use of thermally bridging bricks again) and the plasterboard with polystyrene beads, tapping the plasterboard to help the beads settle. This works thousands of times better than foil radiator deflectors.

The void between the plasterboard and the blockwork under a window filled with insulating polystyrene beads

The top of the plasterboard below a window board is then filled with foam and the window board refitted leaving no paths for draughts to get in.

more here on problems with a WC and understair void http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12952&page=1#Item_16

A couple more pics from the void under the staircase. I assume the XPS should be in the void instead of missing as shown with nice draughts coming through the blocks in the floor? Plan on removing the scree to get back to the XPS somewhere between the void and hopefully the cloakroom.Shot 1http://1drv.ms/1DwzjbmShot 2http://1drv.ms/14gVfYRShot 3http://1drv.ms/14gXlI6Also had another surprise when removing the plasterboard, looks as though the insulation wasn’t the only thing here corners were cut. Thankfully I didn’t get a nasty shock!Wiringhttp://1drv.ms/14gWLKg

The cloakroom is coming along slowly due to work commitments, only getting about a day a week to do anything useful.

I have sealed up the many voids under the stairs and used foam as well as tape to reduce air leakage / entry. Appreciate any comments especially around the type of insulation to use on the floor of the void under the stairs which is normally inaccessible. I was thinking warmcell or EPS beads, but maybe I should match the existing insulation and go with XPS?

Finally, after blocking the large voids some of the smaller ones become more apparent. This is the junction of the internal wall and external wall and I could feel with my hand a cold draught. The pic shows the small amount of “spoil” that was the mortar. Now removed and foamed, next will be the parge coat:http://1drv.ms/1FlLNlV

Remarkably this year 2017 we have seen for the first time a lot of problems with uPVC doors. In previous years we rarely saw problems with these doors.
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